As mentioned, there really ain't many cheap AC fares. The only thing I can think of at this point is SFO-TPE starting in September. SFO-YVR-TPE-YVR-SFO with a 90 minute turn in TPE (same plane) comes to $697.30 after taxes for a weekday-weekday departure. One free stopover allowed.
AC's SFO-YVR routing doesn't allow going through PDX or SEA
ROUTING 16 FROM-TO SFO-AC-DEN-AC-YYC-AC-YEA-AC-
YPE-AC-YXE/YQR-AC-YVR*
FROM-TO SFO-AC-YYC-AC-YVR*
And once you are in Canada, the domestic segments only give you 50% mileage...